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Apache XML Security for Java supports XML-Signature Syntax and Processing,
W3C Recommendation 12 February 2002, and XML Encryption Syntax and
Processing, W3C Recommendation 10 December 2002. As of version 1.4,
the library supports the standard Java API JSR-105: XML Digital Signature APIs.
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.xml.security.signature;
import java.io.IOException;
import java.io.OutputStream;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.apache.xml.security.algorithms.MessageDigestAlgorithm;
import org.apache.xml.security.c14n.CanonicalizationException;
import org.apache.xml.security.c14n.InvalidCanonicalizerException;
import org.apache.xml.security.exceptions.Base64DecodingException;
import org.apache.xml.security.exceptions.XMLSecurityException;
import org.apache.xml.security.signature.reference.ReferenceData;
import org.apache.xml.security.signature.reference.ReferenceNodeSetData;
import org.apache.xml.security.signature.reference.ReferenceOctetStreamData;
import org.apache.xml.security.signature.reference.ReferenceSubTreeData;
import org.apache.xml.security.transforms.InvalidTransformException;
import org.apache.xml.security.transforms.Transform;
import org.apache.xml.security.transforms.TransformationException;
import org.apache.xml.security.transforms.Transforms;
import org.apache.xml.security.transforms.params.InclusiveNamespaces;
import org.apache.xml.security.utils.Base64;
import org.apache.xml.security.utils.Constants;
import org.apache.xml.security.utils.DigesterOutputStream;
import org.apache.xml.security.utils.SignatureElementProxy;
import org.apache.xml.security.utils.UnsyncBufferedOutputStream;
import org.apache.xml.security.utils.XMLUtils;
import org.apache.xml.security.utils.resolver.ResourceResolver;
import org.apache.xml.security.utils.resolver.ResourceResolverException;
import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.Text;
/**
* Handles <ds:Reference> elements.
*
* This includes:
*
* Constuct a ds:Reference from an {@link org.w3c.dom.Element}.
*
* Create a new reference
*
* Document doc;
* MessageDigestAlgorithm sha1 = MessageDigestAlgorithm.getInstance("http://#sha1");
* Reference ref = new Reference(new XMLSignatureInput(new FileInputStream("1.gif"),
* "http://localhost/1.gif",
* (Transforms) null, sha1);
* Element refElem = ref.toElement(doc);
*
*
* Verify a reference
*
* Element refElem = doc.getElement("Reference"); // PSEUDO
* Reference ref = new Reference(refElem);
* String url = ref.getURI();
* ref.setData(new XMLSignatureInput(new FileInputStream(url)));
* if (ref.verify()) {
* System.out.println("verified");
* }
*
*
*
* <element name="Reference" type="ds:ReferenceType"/>
* <complexType name="ReferenceType">
* <sequence>
* <element ref="ds:Transforms" minOccurs="0"/>
* <element ref="ds:DigestMethod"/>
* <element ref="ds:DigestValue"/>
* </sequence>
* <attribute name="Id" type="ID" use="optional"/>
* <attribute name="URI" type="anyURI" use="optional"/>
* <attribute name="Type" type="anyURI" use="optional"/>
* </complexType>
*
*
* @author Christian Geuer-Pollmann
* @see ObjectContainer
* @see Manifest
*/
public class Reference extends SignatureElementProxy {
/** Field OBJECT_URI */
public static final String OBJECT_URI = Constants.SignatureSpecNS + Constants._TAG_OBJECT;
/** Field MANIFEST_URI */
public static final String MANIFEST_URI = Constants.SignatureSpecNS + Constants._TAG_MANIFEST;
/**
* The maximum number of transforms per reference, if secure validation is enabled.
*/
public static final int MAXIMUM_TRANSFORM_COUNT = 5;
private boolean secureValidation;
/**
* Look up useC14N11 system property. If true, an explicit C14N11 transform
* will be added if necessary when generating the signature. See section
* 3.1.1 of http://www.w3.org/2007/xmlsec/Drafts/xmldsig-core/ for more info.
*/
private static boolean useC14N11 = ((Boolean)
AccessController.doPrivileged(new PrivilegedAction() {
public Boolean run() {
return Boolean.valueOf(Boolean.getBoolean("org.apache.xml.security.useC14N11"));
}
})).booleanValue();
/** {@link org.apache.commons.logging} logging facility */
private static final org.apache.commons.logging.Log log =
org.apache.commons.logging.LogFactory.getLog(Reference.class);
private Manifest manifest = null;
private XMLSignatureInput transformsOutput;
private Transforms transforms;
private Element digestMethodElem;
private Element digestValueElement;
private ReferenceData referenceData;
/**
* Constructor Reference
*
* @param doc the {@link Document} in which XMLsignature is placed
* @param BaseURI the URI of the resource where the XML instance will be stored
* @param ReferenceURI URI indicate where is data which will digested
* @param manifest
* @param transforms {@link Transforms} applied to data
* @param messageDigestAlgorithm {@link MessageDigestAlgorithm Digest algorithm} which is
* applied to the data
* TODO should we throw XMLSignatureException if MessageDigestAlgoURI is wrong?
* @throws XMLSignatureException
*/
protected Reference(
Document doc, String BaseURI, String ReferenceURI, Manifest manifest,
Transforms transforms, String messageDigestAlgorithm
) throws XMLSignatureException {
super(doc);
XMLUtils.addReturnToElement(this.constructionElement);
this.baseURI = BaseURI;
this.manifest = manifest;
this.setURI(ReferenceURI);
// important: The ds:Reference must be added to the associated ds:Manifest
// or ds:SignedInfo _before_ the this.resolverResult() is called.
// this.manifest.appendChild(this.constructionElement);
// this.manifest.appendChild(this.doc.createTextNode("\n"));
if (transforms != null) {
this.transforms=transforms;
this.constructionElement.appendChild(transforms.getElement());
XMLUtils.addReturnToElement(this.constructionElement);
}
MessageDigestAlgorithm mda =
MessageDigestAlgorithm.getInstance(this.doc, messageDigestAlgorithm);
digestMethodElem = mda.getElement();
this.constructionElement.appendChild(digestMethodElem);
XMLUtils.addReturnToElement(this.constructionElement);
digestValueElement =
XMLUtils.createElementInSignatureSpace(this.doc, Constants._TAG_DIGESTVALUE);
this.constructionElement.appendChild(digestValueElement);
XMLUtils.addReturnToElement(this.constructionElement);
}
/**
* Build a {@link Reference} from an {@link Element}
*
* @param element Reference element
* @param BaseURI the URI of the resource where the XML instance was stored
* @param manifest is the {@link Manifest} of {@link SignedInfo} in which the Reference occurs.
* We need this because the Manifest has the individual {@link ResourceResolver}s which have
* been set by the user
* @throws XMLSecurityException
*/
protected Reference(Element element, String BaseURI, Manifest manifest) throws XMLSecurityException {
this(element, BaseURI, manifest, false);
}
/**
* Build a {@link Reference} from an {@link Element}
*
* @param element Reference element
* @param BaseURI the URI of the resource where the XML instance was stored
* @param manifest is the {@link Manifest} of {@link SignedInfo} in which the Reference occurs.
* @param secureValidation whether secure validation is enabled or not
* We need this because the Manifest has the individual {@link ResourceResolver}s which have
* been set by the user
* @throws XMLSecurityException
*/
protected Reference(Element element, String BaseURI, Manifest manifest, boolean secureValidation)
throws XMLSecurityException {
super(element, BaseURI);
this.secureValidation = secureValidation;
this.baseURI = BaseURI;
Element el = XMLUtils.getNextElement(element.getFirstChild());
if (Constants._TAG_TRANSFORMS.equals(el.getLocalName())
&& Constants.SignatureSpecNS.equals(el.getNamespaceURI())) {
transforms = new Transforms(el, this.baseURI);
transforms.setSecureValidation(secureValidation);
if (secureValidation && transforms.getLength() > MAXIMUM_TRANSFORM_COUNT) {
Object exArgs[] = { transforms.getLength(), MAXIMUM_TRANSFORM_COUNT };
throw new XMLSecurityException("signature.tooManyTransforms", exArgs);
}
el = XMLUtils.getNextElement(el.getNextSibling());
}
digestMethodElem = el;
digestValueElement = XMLUtils.getNextElement(digestMethodElem.getNextSibling());
this.manifest = manifest;
}
/**
* Returns {@link MessageDigestAlgorithm}
*
*
* @return {@link MessageDigestAlgorithm}
*
* @throws XMLSignatureException
*/
public MessageDigestAlgorithm getMessageDigestAlgorithm() throws XMLSignatureException {
if (digestMethodElem == null) {
return null;
}
String uri = digestMethodElem.getAttributeNS(null, Constants._ATT_ALGORITHM);
if (uri == null) {
return null;
}
if (secureValidation && MessageDigestAlgorithm.ALGO_ID_DIGEST_NOT_RECOMMENDED_MD5.equals(uri)) {
Object exArgs[] = { uri };
throw new XMLSignatureException("signature.signatureAlgorithm", exArgs);
}
return MessageDigestAlgorithm.getInstance(this.doc, uri);
}
/**
* Sets the URI of this Reference element
*
* @param URI the URI of this Reference element
*/
public void setURI(String URI) {
if (URI != null) {
this.constructionElement.setAttributeNS(null, Constants._ATT_URI, URI);
}
}
/**
* Returns the URI of this Reference element
*
* @return URI the URI of this Reference element
*/
public String getURI() {
return this.constructionElement.getAttributeNS(null, Constants._ATT_URI);
}
/**
* Sets the Id attribute of this Reference element
*
* @param Id the Id attribute of this Reference element
*/
public void setId(String Id) {
if (Id != null) {
this.constructionElement.setAttributeNS(null, Constants._ATT_ID, Id);
this.constructionElement.setIdAttributeNS(null, Constants._ATT_ID, true);
}
}
/**
* Returns the Id attribute of this Reference element
*
* @return Id the Id attribute of this Reference element
*/
public String getId() {
return this.constructionElement.getAttributeNS(null, Constants._ATT_ID);
}
/**
* Sets the type atttibute of the Reference indicate whether an
* ds:Object, ds:SignatureProperty, or ds:Manifest
* element.
*
* @param Type the type attribute of the Reference
*/
public void setType(String Type) {
if (Type != null) {
this.constructionElement.setAttributeNS(null, Constants._ATT_TYPE, Type);
}
}
/**
* Return the type atttibute of the Reference indicate whether an
* ds:Object, ds:SignatureProperty, or ds:Manifest
* element
*
* @return the type attribute of the Reference
*/
public String getType() {
return this.constructionElement.getAttributeNS(null, Constants._ATT_TYPE);
}
/**
* Method isReferenceToObject
*
* This returns true if the Type attribute of the
* Reference element points to a #Object element
*
* @return true if the Reference type indicates that this Reference points to an
* Object
*/
public boolean typeIsReferenceToObject() {
if (Reference.OBJECT_URI.equals(this.getType())) {
return true;
}
return false;
}
/**
* Method isReferenceToManifest
*
* This returns true if the Type attribute of the
* Reference element points to a #Manifest element
*
* @return true if the Reference type indicates that this Reference points to a
* {@link Manifest}
*/
public boolean typeIsReferenceToManifest() {
if (Reference.MANIFEST_URI.equals(this.getType())) {
return true;
}
return false;
}
/**
* Method setDigestValueElement
*
* @param digestValue
*/
private void setDigestValueElement(byte[] digestValue) {
Node n = digestValueElement.getFirstChild();
while (n != null) {
digestValueElement.removeChild(n);
n = n.getNextSibling();
}
String base64codedValue = Base64.encode(digestValue);
Text t = this.doc.createTextNode(base64codedValue);
digestValueElement.appendChild(t);
}
/**
* Method generateDigestValue
*
* @throws ReferenceNotInitializedException
* @throws XMLSignatureException
*/
public void generateDigestValue()
throws XMLSignatureException, ReferenceNotInitializedException {
this.setDigestValueElement(this.calculateDigest(false));
}
/**
* Returns the XMLSignatureInput which is created by de-referencing the URI attribute.
* @return the XMLSignatureInput of the source of this reference
* @throws ReferenceNotInitializedException If the resolver found any
* problem resolving the reference
*/
public XMLSignatureInput getContentsBeforeTransformation()
throws ReferenceNotInitializedException {
try {
Attr URIAttr =
this.constructionElement.getAttributeNodeNS(null, Constants._ATT_URI);
String URI;
if (URIAttr == null) {
URI = null;
} else {
URI = URIAttr.getNodeValue();
}
ResourceResolver resolver =
ResourceResolver.getInstance(
URIAttr, this.baseURI, this.manifest.getPerManifestResolvers(), secureValidation
);
if (resolver == null) {
Object exArgs[] = { URI };
throw new ReferenceNotInitializedException(
"signature.Verification.Reference.NoInput", exArgs
);
}
resolver.addProperties(this.manifest.getResolverProperties());
return resolver.resolve(URIAttr, this.baseURI);
} catch (ResourceResolverException ex) {
throw new ReferenceNotInitializedException("empty", ex);
} catch (XMLSecurityException ex) {
throw new ReferenceNotInitializedException("empty", ex);
}
}
private XMLSignatureInput getContentsAfterTransformation(
XMLSignatureInput input, OutputStream os
) throws XMLSignatureException {
try {
Transforms transforms = this.getTransforms();
XMLSignatureInput output = null;
if (transforms != null) {
output = transforms.performTransforms(input,os);
this.transformsOutput = output;//new XMLSignatureInput(output.getBytes());
//this.transformsOutput.setSourceURI(output.getSourceURI());
} else {
output = input;
}
return output;
} catch (ResourceResolverException ex) {
throw new XMLSignatureException("empty", ex);
} catch (CanonicalizationException ex) {
throw new XMLSignatureException("empty", ex);
} catch (InvalidCanonicalizerException ex) {
throw new XMLSignatureException("empty", ex);
} catch (TransformationException ex) {
throw new XMLSignatureException("empty", ex);
} catch (XMLSecurityException ex) {
throw new XMLSignatureException("empty", ex);
}
}
/**
* Returns the XMLSignatureInput which is the result of the Transforms.
* @return a XMLSignatureInput with all transformations applied.
* @throws XMLSignatureException
*/
public XMLSignatureInput getContentsAfterTransformation()
throws XMLSignatureException {
XMLSignatureInput input = this.getContentsBeforeTransformation();
cacheDereferencedElement(input);
return this.getContentsAfterTransformation(input, null);
}
/**
* This method returns the XMLSignatureInput which represents the node set before
* some kind of canonicalization is applied for the first time.
* @return Gets a the node doing everything till the first c14n is needed
*
* @throws XMLSignatureException
*/
public XMLSignatureInput getNodesetBeforeFirstCanonicalization()
throws XMLSignatureException {
try {
XMLSignatureInput input = this.getContentsBeforeTransformation();
cacheDereferencedElement(input);
XMLSignatureInput output = input;
Transforms transforms = this.getTransforms();
if (transforms != null) {
doTransforms: for (int i = 0; i < transforms.getLength(); i++) {
Transform t = transforms.item(i);
String URI = t.getURI();
if (URI.equals(Transforms.TRANSFORM_C14N_EXCL_OMIT_COMMENTS)
|| URI.equals(Transforms.TRANSFORM_C14N_EXCL_WITH_COMMENTS)
|| URI.equals(Transforms.TRANSFORM_C14N_OMIT_COMMENTS)
|| URI.equals(Transforms.TRANSFORM_C14N_WITH_COMMENTS)) {
break doTransforms;
}
output = t.performTransform(output, null);
}
output.setSourceURI(input.getSourceURI());
}
return output;
} catch (IOException ex) {
throw new XMLSignatureException("empty", ex);
} catch (ResourceResolverException ex) {
throw new XMLSignatureException("empty", ex);
} catch (CanonicalizationException ex) {
throw new XMLSignatureException("empty", ex);
} catch (InvalidCanonicalizerException ex) {
throw new XMLSignatureException("empty", ex);
} catch (TransformationException ex) {
throw new XMLSignatureException("empty", ex);
} catch (XMLSecurityException ex) {
throw new XMLSignatureException("empty", ex);
}
}
/**
* Method getHTMLRepresentation
* @return The HTML of the transformation
* @throws XMLSignatureException
*/
public String getHTMLRepresentation() throws XMLSignatureException {
try {
XMLSignatureInput nodes = this.getNodesetBeforeFirstCanonicalization();
Transforms transforms = this.getTransforms();
Transform c14nTransform = null;
if (transforms != null) {
doTransforms: for (int i = 0; i < transforms.getLength(); i++) {
Transform t = transforms.item(i);
String URI = t.getURI();
if (URI.equals(Transforms.TRANSFORM_C14N_EXCL_OMIT_COMMENTS)
|| URI.equals(Transforms.TRANSFORM_C14N_EXCL_WITH_COMMENTS)) {
c14nTransform = t;
break doTransforms;
}
}
}
Set inclusiveNamespaces = new HashSet();
if (c14nTransform != null
&& (c14nTransform.length(
InclusiveNamespaces.ExclusiveCanonicalizationNamespace,
InclusiveNamespaces._TAG_EC_INCLUSIVENAMESPACES) == 1)) {
// there is one InclusiveNamespaces element
InclusiveNamespaces in =
new InclusiveNamespaces(
XMLUtils.selectNode(
c14nTransform.getElement().getFirstChild(),
InclusiveNamespaces.ExclusiveCanonicalizationNamespace,
InclusiveNamespaces._TAG_EC_INCLUSIVENAMESPACES,
0
), this.getBaseURI());
inclusiveNamespaces =
InclusiveNamespaces.prefixStr2Set(in.getInclusiveNamespaces());
}
return nodes.getHTMLRepresentation(inclusiveNamespaces);
} catch (TransformationException ex) {
throw new XMLSignatureException("empty", ex);
} catch (InvalidTransformException ex) {
throw new XMLSignatureException("empty", ex);
} catch (XMLSecurityException ex) {
throw new XMLSignatureException("empty", ex);
}
}
/**
* This method only works works after a call to verify.
* @return the transformed output(i.e. what is going to be digested).
*/
public XMLSignatureInput getTransformsOutput() {
return this.transformsOutput;
}
/**
* Get the ReferenceData that corresponds to the cached representation of the dereferenced
* object before transformation.
*/
public ReferenceData getReferenceData() {
return referenceData;
}
/**
* This method returns the {@link XMLSignatureInput} which is referenced by the
* URI Attribute.
* @param os where to write the transformation can be null.
* @return the element to digest
*
* @throws XMLSignatureException
* @see Manifest#verifyReferences()
*/
protected XMLSignatureInput dereferenceURIandPerformTransforms(OutputStream os)
throws XMLSignatureException {
try {
XMLSignatureInput input = this.getContentsBeforeTransformation();
cacheDereferencedElement(input);
XMLSignatureInput output = this.getContentsAfterTransformation(input, os);
this.transformsOutput = output;
return output;
} catch (XMLSecurityException ex) {
throw new ReferenceNotInitializedException("empty", ex);
}
}
/**
* Store the dereferenced Element(s) so that it/they can be retrieved later.
*/
private void cacheDereferencedElement(XMLSignatureInput input) {
if (input.isNodeSet()) {
try {
final Set s = input.getNodeSet();
referenceData = new ReferenceNodeSetData() {
public Iterator iterator() { return s.iterator(); }
};
} catch (Exception e) {
// log a warning
log.warn("cannot cache dereferenced data: " + e);
}
} else if (input.isElement()) {
referenceData = new ReferenceSubTreeData
(input.getSubNode(), input.isExcludeComments());
} else if (input.isOctetStream() || input.isByteArray()) {
try {
referenceData = new ReferenceOctetStreamData
(input.getOctetStream(), input.getSourceURI(),
input.getMIMEType());
} catch (IOException ioe) {
// log a warning
log.warn("cannot cache dereferenced data: " + ioe);
}
}
}
/**
* Method getTransforms
*
* @return The transforms that applied this reference.
* @throws InvalidTransformException
* @throws TransformationException
* @throws XMLSecurityException
* @throws XMLSignatureException
*/
public Transforms getTransforms()
throws XMLSignatureException, InvalidTransformException,
TransformationException, XMLSecurityException {
return transforms;
}
/**
* Method getReferencedBytes
*
* @return the bytes that will be used to generated digest.
* @throws ReferenceNotInitializedException
* @throws XMLSignatureException
*/
public byte[] getReferencedBytes()
throws ReferenceNotInitializedException, XMLSignatureException {
try {
XMLSignatureInput output = this.dereferenceURIandPerformTransforms(null);
return output.getBytes();
} catch (IOException ex) {
throw new ReferenceNotInitializedException("empty", ex);
} catch (CanonicalizationException ex) {
throw new ReferenceNotInitializedException("empty", ex);
}
}
/**
* Method calculateDigest
*
* @param validating true if validating the reference
* @return reference Calculate the digest of this reference.
* @throws ReferenceNotInitializedException
* @throws XMLSignatureException
*/
private byte[] calculateDigest(boolean validating)
throws ReferenceNotInitializedException, XMLSignatureException {
try {
MessageDigestAlgorithm mda = this.getMessageDigestAlgorithm();
mda.reset();
DigesterOutputStream diOs = new DigesterOutputStream(mda);
OutputStream os = new UnsyncBufferedOutputStream(diOs);
XMLSignatureInput output = this.dereferenceURIandPerformTransforms(os);
// if signing and c14n11 property == true explicitly add
// C14N11 transform if needed
if (Reference.useC14N11 && !validating && !output.isOutputStreamSet()
&& !output.isOctetStream()) {
if (transforms == null) {
transforms = new Transforms(this.doc);
transforms.setSecureValidation(secureValidation);
this.constructionElement.insertBefore(transforms.getElement(), digestMethodElem);
}
transforms.addTransform(Transforms.TRANSFORM_C14N11_OMIT_COMMENTS);
output.updateOutputStream(os, true);
} else {
output.updateOutputStream(os);
}
os.flush();
//this.getReferencedBytes(diOs);
//mda.update(data);
return diOs.getDigestValue();
} catch (XMLSecurityException ex) {
throw new ReferenceNotInitializedException("empty", ex);
} catch (IOException ex) {
throw new ReferenceNotInitializedException("empty", ex);
}
}
/**
* Returns the digest value.
*
* @return the digest value.
* @throws Base64DecodingException if Reference contains no proper base64 encoded data.
* @throws XMLSecurityException if the Reference does not contain a DigestValue element
*/
public byte[] getDigestValue() throws Base64DecodingException, XMLSecurityException {
if (digestValueElement == null) {
// The required element is not in the XML!
Object[] exArgs ={ Constants._TAG_DIGESTVALUE, Constants.SignatureSpecNS };
throw new XMLSecurityException(
"signature.Verification.NoSignatureElement", exArgs
);
}
return Base64.decode(digestValueElement);
}
/**
* Tests reference validation is success or false
*
* @return true if reference validation is success, otherwise false
* @throws ReferenceNotInitializedException
* @throws XMLSecurityException
*/
public boolean verify()
throws ReferenceNotInitializedException, XMLSecurityException {
byte[] elemDig = this.getDigestValue();
byte[] calcDig = this.calculateDigest(true);
boolean equal = MessageDigestAlgorithm.isEqual(elemDig, calcDig);
if (!equal) {
log.warn("Verification failed for URI \"" + this.getURI() + "\"");
log.warn("Expected Digest: " + Base64.encode(elemDig));
log.warn("Actual Digest: " + Base64.encode(calcDig));
} else {
if (log.isDebugEnabled()) {
log.debug("Verification successful for URI \"" + this.getURI() + "\"");
}
}
return equal;
}
/**
* Method getBaseLocalName
* @inheritDoc
*/
public String getBaseLocalName() {
return Constants._TAG_REFERENCE;
}
}